JPH11144316A - Storage member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable recording with external energy of low power with a storage member which records information by a change in the optical characteristics caused by an oxidation reduction reaction of a first material and second material when the external energy is imparted thereto. SOLUTION: This storage member is constituted by successively laminating a WO3 film 20 consisting of WO3 of <=550 KJ in the energy necessary at the time of dissociation of a 1 mol amt. of oxygen molecules, an Al-Ti alloy film 30 consisting of an alloy contg. <30 atom.% Ti with respect to Al of >=1000 KJ in the energy generated at the time of bonding to the 1 mol amt. of the oxygen molecules and a protective film 40 consisting of a UV curing resin on a transparent substrate 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a storage member for recording information by changing optical characteristics by applying external energy, and is suitable for use in, for example, a write-once compact disc (CD-R). is there.

[0002]

2. Description of the Related Art As this kind of storage member, there is an optical recording medium represented by a compact disk (CD), for example. In general, a recording layer (light absorbing layer) made of an organic dye or the like is provided on a substrate, and a reflective layer made of gold, silver, or the like is further provided thereon, and laser light is irradiated as external energy. Thus, the information is recorded by changing or modifying the recording layer to change the optical characteristics. Then, information is optically reproduced using the difference in reflectance between the recorded portion and the unrecorded portion.

However, since the recording layer is made of an organic material, there is a problem that the cost is high in terms of the cost of the material itself and the production yield. In order to solve these problems, an inorganic material that is inexpensive compared to an organic dye or the like is used, and the recording layer is formed by a normal film forming method superior in cost such as an evaporation method or a sputtering method. Proposed. Examples of using such an inorganic material recording layer include:
For example, those using metal sulfides (for example, SnS) (see JP-A-4-193586) and those using sulfur or selenium (see JP-A-2-152929)
Has been proposed.

[0004]

SUMMARY OF THE INVENTION The present inventors have studied the storage member using the inorganic material recording layer in both of the above publications, and as a result, have found that the storage resistance and the information retention are as follows. Found that there was a problem in terms of That is, in the former publication, information recorded on the recording layer is recorded at high temperature and high humidity (for example, at a temperature of 90 ° C. and a relative humidity of 80% R).
H) If the recording layer is held for a long time (for example, 240 hours) under the condition, the recording layer swells and becomes unreproducible. In the latter publication, the recording layer which should react only during recording is described. (E.g., sulfur) and a reflective layer (e.g., silver) due to high reactivity of the reaction (e.g., the reactant is silver sulfide),
Even when left at room temperature, there is a problem that the reaction gradually proceeds to form a reaction product, and information retention becomes unstable.

Accordingly, the present inventors have previously described Japanese Patent Application No.
Japanese Patent No. 285671 proposes to provide a storage member having excellent environmental resistance and information retention. This is composed of at least two types of substances, a first substance and a second substance, and the information is recorded by the reaction of the two substances due to the application of external energy and the change of the optical characteristic of at least one of the two substances. The present invention proposes two substances that solve the above-mentioned problem when external energy is applied to a storage member within a practical range.

That is, the reaction between the two substances is defined as an oxidation-reduction reaction for supplying oxygen from the second substance to the first substance.
Has the energy (hereinafter referred to as oxygen binding energy) of 1 when it is combined with 1 mol of oxygen molecules.
A metal, an intermetallic compound, a nitride, or the like having a molecular weight of 000 kJ or more, and the second substance contains 1 mol of oxygen molecules.
Energy required for dissociating the amount (hereinafter referred to as oxygen dissociation energy) is 550 kJ or less at least one of an oxide and a substance containing oxygen as a constituent element;
It shall include one.

As a result, the oxidation-reduction reaction of the two substances at the time of recording can be made an exothermic reaction, and the reverse reaction is less likely to occur. As a result, the thermal stability of holding the recorded information and the resistance to moisture are reduced. Stability can be improved. By the way, in the above-mentioned prior application, the aim was to improve the environmental resistance and the retention of information. Therefore, in the configuration of the above-mentioned prior application, the power of external energy (for example, laser light) applied at the time of recording was increased, and the practical application was not practical. (For example, when the laser power is 14 m
W or more), which causes a problem in recording sensitivity. Therefore,
It is desired to study a storage member configuration that enables efficient recording with low-power external energy.

The present invention has been made in view of the problems in the prior application, and records information by applying an external energy to cause a first substance and a second substance to undergo an oxidation-reduction reaction to change optical characteristics. An object of the present invention is to make it possible to perform recording with low-power external energy in a storage member to be used.

[0009]

In order to achieve the above-mentioned object, the present inventors increased the surface area of each substance to increase the reactivity. In other words, the present inventors have made intensive studies on a multi-layer structure in which a first substance (which itself is oxidized) and a second substance on the oxygen supply side (that is, which itself is reduced) form a layer.

As a result of an experimental study on a reflection type storage member which performs recording / reproduction by using a laser beam as external energy, as described below, Ti or a Ti compound is added for the recording laser power. It has been found that it is suitable as a product. The reason for examining the recording laser power is that the recording laser power is the first layer forming the first layer.
This is because it is the power of the laser beam required for the oxidation-reduction reaction between the substance and the second substance forming the second layer, that is, the laser light required for recording. According to the study by the present inventors, as a practical level, a recording laser power of less than 14 mW is desirable.

The memory member used in the experiment was as shown in FIGS. Here, the first substance is referred to as A, which is one of the substances constituting the first substance in the above-mentioned prior application.
A is an alloy in which Ti is added at a desired ratio to 1
An l-Ti alloy is used, and the second substance is WO ₃ which is one of the substances constituting the second substance in the above-mentioned prior application. Then, the two materials are formed into a laminated structure, and the application of laser light causes an oxidation-reduction reaction between the Al—Ti alloy film (first layer) 30 and the WO ₃ film (second layer) 20, and the recording / reproduction is performed as a change in reflectance. Shall do.

As shown in FIG. 1, the memory member 1 has a disk shape as a whole, having a hole 2 formed in the center. A flat portion 3 on which information is not recorded is provided around the outer periphery of the hole 2, and a recording portion 4 on which information is recorded and reproduced is provided on the outer periphery of the flat portion 3. The recording section 4 will be described with reference to FIG. WO ₃ is formed on a surface 12 of a transparent substrate 10 made of polycarbonate formed into a disk (for example, 1.2 mm in thickness) by RF magnetron sputtering using a W target.
A film 20 is formed with a thickness of 190 nm, and an Al—Ti alloy film 30 is formed on the WO ₃ film 20 by RF magnetron sputtering using an Al—Ti alloy target.
The film is formed to a thickness of 0 nm. On the Al-Ti alloy film 30, a protective film 40 is formed by an ultraviolet curable resin.

The storage member 1 is provided with a surface 11 of the substrate 10.
From the side (in the direction of arrow A shown in FIG. 1), a laser beam having a wavelength of 780 nm is focused on the surface of the Al—Ti alloy film 30 through an objective lens having an NA (numerical aperture) of 0.50, and recording is performed. At this time, the power of the laser beam at the time when the recording was performed by the reaction of both substances of both films 20 and 30 was defined as the recording laser power.

FIG. 3 is a graph showing the result of examining the recording laser power (mW) in this storage member 1 by changing the amount of Ti (atomic%) in the Al—Ti alloy film 30. From this, when the Ti amount is 0, that is, when Al alone is used, the recording laser power is 14 mW, exceeding the practical level.
It has been found that the recording laser power can be reduced to less than 14 mW by adding i, and the recording laser power can be reduced as the amount of Ti added increases.

The effect of the addition of Ti is that Ti is an active metal, so that the surface is easily oxidized, and that it easily absorbs recording laser light (for example, a wavelength of 780 nm), so that heat is easily absorbed. This is probably because the addition increases the reactivity. Therefore, it is considered that the same addition effect can be obtained even when it is added to a substance other than Al, and this addition effect is exerted not only by Ti but also by a Ti compound.

In the same manner as in the above-mentioned experimental study, the various materials constituting the first material in the above-mentioned prior application were changed to Ti
Alternatively, when the recording laser power was examined by adding a Ti compound, it was found that the recording laser power could be reduced by adding Ti or the Ti compound. The invention according to claim 1 has been made based on the above findings, and has a plurality of layers including a first layer made of a first substance and a second layer made of a second substance, and imparts external energy. A storage member for recording information by changing an optical characteristic of at least one of the two substances by performing an oxidation-reduction reaction for supplying oxygen from the second substance to the first substance. Is a substance containing at least one of an oxide and a substance containing oxygen whose energy required for dissociating 1 mol of oxygen molecules is 550 kJ or less, and the first substance is Oxygen molecule 1 mo
The energy generated when combining with the amount of l is 1000k
Ti or a Ti compound (hereinafter, referred to as Ti, etc.) is contained in a substance (hereinafter, referred to as a first-stage substance) composed of at least one of a metal, an intermetallic compound, a nitride, and a compound including these metals having J or more. It is characterized in that it is.

Here, “the former substance contains Ti or the like” means that Ti or the like is an alloy with the former substance or a compound with the former substance such as an intermetallic compound or a nitride.
Alternatively, it means that it is contained as a mixture with the preceding substance. Further, the former substance may be Ti or the like, in which case, the entire first substance is made of a substance such as Ti. The Ti compound may be TiN (titanium nitride) or a substance containing TiN.

Thereby, the reactivity of the first substance in the first layer is increased, and external energy (eg, laser light) applied at the time of recording is reduced to a low power (eg, laser light) within a practical range.
Even when the laser power is less than 14 mW, the redox reaction between the first substance and the second substance is performed. Therefore, it is possible to provide a storage member that can be recorded with low-power external energy.

Further, it is expected that the addition of Ti or the like increases the light absorptivity, lowers the light transmittance, and affects the optical characteristics (eg, reflectance) of the storage member.
The study was conducted in consideration of the relationship between the addition amount of i and the like and the optical characteristics of the storage member. Here, as the optical characteristics, an unrecorded portion reflectance, which is an important characteristic in terms of recording sensitivity, was examined.

Here, the reason for examining the unrecorded portion reflectance is as follows.
The unrecorded portion reflectance is a reflectance at the time of reproduction of a portion other than the recorded portion, and is largely affected by the light transmittance of the first layer, that is, the thickness of the first layer. According to the study of the present inventors, as a practical level, it is desirable that the unrecorded portion reflectance is 60% or more. In the storage member similar to that in the above experimental study, that is, in the storage member 1 shown in FIGS. 1 and 2, the amount of Ti (atomic%) with respect to Al, which is the former substance in the Al—Ti alloy film 30, was changed to reflect the unrecorded portion. The rate was checked. The unrecorded portion reflectance was determined by measuring the reflectance of the unrecorded portion of the recording portion 4 at a recording laser power of 0.7 mW (wavelength = 780 nm) of the recorded storage member 1. The results are shown in FIG. 4 as a graph showing the relationship between the amount (atomic%) of Ti with respect to Al and the reflectance (%) of the unrecorded portion.

FIG. 4 shows that if the amount of Ti with respect to Al is less than 30 atomic%, the unrecorded portion reflectivity 6 which is a practical level is obtained.
It is understood that 0% or more is satisfied. Similarly, when the various materials constituting the first material were examined in the above-mentioned prior application, it was found that the reflectance of unrecorded portions was 60% or more when the amount of Ti to Al was less than 30 atomic%. Therefore,
If Ti or the like contained in the first substance according to claim 1 is less than 30 atomic% as Ti atoms, the optical characteristics of the storage member can be maintained at a practical level (for example, the unrecorded portion reflectance is 60% or more). The recording can be performed with low power external energy (for example, recording laser power of less than 14 mW).

The second substance constituting the second layer is preferably a substance which itself is reduced by oxidizing the first substance. Examples of such a substance are as follows. Can be That is, the second substance is composed of groups 6, 8, 9, 11, and Ti, V, M in the periodic table.
n, Ni, Re, Ge, Sn, Pb, As, Sb, B
The material can be an oxide containing at least one element selected from i, Se, Te, Ce, Pr, and Tb, and a substance containing at least one of oxygen-containing substances. Here, for example, Cr,
Mo, W, etc., Group 8 elements such as Fe and Ru, Group 9 elements such as Co, Rh, Ir, etc., and Group 11 elements such as C
u, Ag, Au and the like.

If the first substance and the second substance are inorganic materials as described above, the materials themselves are less expensive than a memory member using an organic material such as an organic dye, and Because it can be manufactured by a known method such as a vapor deposition method or a sputtering method,
It can be a cost-effective storage material. Furthermore, if the first layer and the second layer are in contact with each other,
When external energy is applied, the redox reaction between the first substance and the second substance is more likely to occur, and the sensitivity of the storage member can be improved.

Further, if a third substance having a decomposition temperature of 300 ° C. or less is interposed between the first layer and the second layer, the heat retention of information is more excellent. I can do it. Here, the decomposition temperature means that the third substance is decomposed, sublimated,
This is the third temperature at which the decomposition temperature is 300 ° C or lower
As the substance, for example, hydrocarbon or the like can be used.

That is, by heating above the decomposition temperature by external energy, the third substance is decomposed, sublimated, melted, etc., and the first substance and the second substance can react, and information can be recorded. Becomes Before recording, since the third substance is interposed between the first substance and the second substance, the reaction between the two substances at a decomposition temperature or lower is suppressed. Therefore, the optical characteristics can be maintained at a practical level, and recording can be performed with low-power external energy, and the heat retention performance can be improved.

The decomposition temperature of the intervening third substance is set to 3
The reason why the temperature is set to 00 ° C. or less is that if the temperature is higher than 300 ° C., the external energy given at the time of recording must be very large, which is not practical.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present embodiment, a description will be given of a case where the Ti content of the Al—Ti alloy film 30 in the above-mentioned storage member 1 shown in FIGS. 1 and 2 is 25 atomic%. As shown in FIG. 1, the storage member 1 has a disc shape as a whole, in which a hole 2 for attaching to a CD player or the like is formed in the center portion, and is provided with the flat portion 3 and the recording portion 4 as described above. I have.

Regarding the cross-sectional structure of the recording section 4, the description of the portion described above with reference to FIG. One surface 11 of the substrate 10 on the laser light incident side is a mirror surface, and a spiral or concentric guide groove (not shown) for guiding the laser light is formed on the other surface 12. A laser beam for recording and reproducing optical information is incident from the substrate 10 as shown by an arrow A, and is reflected by the Al-Ti alloy film 30 in a direction opposite to the arrow A as described later.

Next, a method for manufacturing the storage member 1 will be described. First, the WO ₃ film 20 is firstly subjected to a gas type (RF) magnetron sputtering method on a surface 12 of a substrate 10 which is a polycarbonate disk having guide grooves formed on one side and a guide groove formed on the other side by RF magnetron sputtering. Pressure ratio): O ₂ /
(Ar + O ₂ ) = 0.1, sputtering gas pressure: 3.0 × 1
Under a film forming condition of 0 ^-3 Torr, input power: 100 to 300 W, a film is formed to a thickness of 190 nm using a W target.

Subsequently, without breaking the vacuum, the Al—Ti alloy film 30 was formed by RF magnetron sputtering with a gas species of Ar, a sputtering gas pressure of 3.0 × 10 ⁻³ Torr, and an input power of 100 to 200 W. Depending on the film conditions, Al-2
It is formed to a thickness of 50 nm using a 5 atomic% Ti alloy target. Finally, an ultraviolet curing resin is applied by a spin coating method, and the ultraviolet curing resin is cured using a high-pressure mercury lamp to form a resin film, and a protective film 40 is formed. Thus,
The storage member 1 is completed.

Next, an experiment was conducted on the performance of the storage member 1 as follows. The storage member 1 has the surface 1 of the substrate 10
1 (mirror surface) side, laser light of wavelength = 780 nm
Through an objective lens of A (numerical aperture) = 0.50, Al-
Light was condensed and recorded on the surface of the Ti alloy film 30. At this time,
Linear velocity = 2.8 m / sec, recording frequency = 400 kHz
z, recording laser waveform = rectangular wave with a duty ratio of 50%, and recording laser power = 10 mW.

The recorded storage member 1 is subjected to C / N (c) at a reproduction laser power of 0.7 mW (wavelength = 780 nm).
The reflectivity of an unrecorded portion and a recorded portion (recorded pit) was measured. As a result, C / N = 50 dB, unrecorded portion reflectance = 68%,
The reflectance of the recording portion was 11%. Thus, it was confirmed that the storage member 1 exhibited good optical characteristics.

Here, a semiconductor laser beam or the like is practically used as the laser beam, and it is generally desired that the recording laser power be within a range of less than 14 mW as a practical level. In this example, the recording laser power can be kept within the practical level range of 10 mW while maintaining the practical level of the unrecorded portion reflectance of 60% or more, and recording can be performed with low power. Further, the recorded storage member 1 is used as an environmental resistance test.
After holding for 240 hours in an environment of a temperature of 90 ° C. and a relative humidity of 80% RH, the C / N, the reflectance of the unrecorded portion, and the reflectance of the recorded portion were measured again. No change was observed in the characteristics of As described above, it was confirmed that the storage member 1 has a stable recording information retention performance against heat and moisture.

By the way, the memory member 1, the recording laser beam, mainly changing the light energy into heat by absorbing in the vicinity of the interface between the WO ₃ film 20 and the Al-Ti alloy film 30, WO ₃ film 20 in this energy And a reaction is induced between the Al—Ti alloy film 30 and the Al—Ti alloy film 30. The reaction is carried out from the WO ₃ film 20 by Al-T
Oxygen is supplied to the i-alloy film 30 and the Al-Ti alloy film 30
All or part of, changes in at least one of the Al ₂ O ₃ film and the TiO film, whereas all or part of the WO ₃ film 20 is changed to the WO _{2. 96} film take oxygen deficiency structure.
In the present embodiment, both films 20 and 30 are formed in the recording unit 4.
The changed part is configured as a recording part.

That is, the WO ₃ film 20 oxidizes the Al—Ti alloy film 30 and is reduced by itself.
A value of 0 means that the WO ₃ film 20 is reduced and oxidized. At this time, the WO ₃ film 20, the Al ₂ O ₃ film and the TiO ₂
Film is a light-absorbing film, Al-Ti alloy film 30 is a film having a metallic luster, WO _{2. 96} film is a light-absorbing film appears colored blue in the visible region.

Therefore, before recording in the above experiment, A
Due to the effect of the l-Ti alloy film 30 as a reflection layer, the reproduction laser beam is reflected 68% on the unrecorded portion of the recording section 4. However, by recording laser beam to absorb is reduced is WO ₃ film 20 is recorded portion of the recording unit 4 having entered WO _{2. 96} film and becomes light, the reproducing laser beam is not reflected only 11%. That is, information is recorded mainly by a change in the optical characteristics of WO ₃ as the second substance. This is the operation that can store information such as data in the present embodiment.

Further, since the entire reaction is an exothermic reaction, once the reaction proceeds by the recording laser beam, the energy supplied by the recording laser beam can be reduced,
As a result, the sensitivity of the storage member 1 can be increased.
At the same time, by selecting a combination of materials having a large exothermic energy for the reaction, the reverse reaction is less likely to occur. Therefore, as a result, it is possible to improve the thermal stability of recording information retention and the stability against moisture.

Energy generated when Al is combined with 1 mol of oxygen molecules (oxygen binding energy)
Is about 1128 kJ, that is, 1000 kJ or more at room temperature. However, it is considered that the alloying with Ti lowers the reaction energy of the oxidation-reduction reaction and suppresses the diffusion of heat, thereby increasing the required recording laser power. Can be Note that WO ₃ dissociates 1 mol of oxygen molecules and WO _3
2. Energy required when changing to ₉₆ (oxygen dissociation energy) is located approximately 413kJ at room temperature 500
kJ or less.

The effect of the addition of Ti is that the surface is easily oxidized because Ti itself is an active metal, that the recording laser light (for example, 780 nm) is easily absorbed, and that heat is easily absorbed. From the suppression, etc., Ti
It is considered that the reactivity is increased by the addition of. Conversely, the addition of Ti increases the light absorption and lowers the light transmittance. However, by setting the addition amount to less than 30 atomic%, the light transmittance is such that the unrecorded portion reflectance of 60% or more can be secured. It is thought that the rate can be kept down.

It should be noted that the Al shown in FIGS.
-In the storage member 1 in which the amount of Ti with respect to Al in the Ti alloy film 30 is variously changed, information is stored by the above-described reaction mechanism. And the recording member 1 that can be recorded with a low-power recording laser can be provided.

As described above, the first layer is formed of Al as a metal film.
By using the -Ti alloy film 30, the recording sensitivity can be increased (the recording laser power is reduced in this embodiment) as compared with the Al-only film, and the optical characteristics of the storage member 1 (as compared to the Ti-only film) ( In the present embodiment, the unrecorded portion reflectance can be increased. In this embodiment, the first layer, the Al—Ti alloy film 30 and the second
Since the WO ₃ film 20 is in contact with each other, when a recording laser beam is incident, the oxidation-reduction reaction of both materials constituting both layers is more likely to occur, and the recording sensitivity of the storage member 1 is improved. It also has the effect that it can be done.

Further, according to the present embodiment, the first substance oxidized and the second substance reduced in the reaction at the time of applying the recording laser beam are laminated on the substrate 10 in layers. Because it has a multi-layer structure, the physique can be made thin,
For example, it is suitable for a write-once compact disc (CD-R). (Other Embodiments) In the above embodiment, the first layer (Al—Ti alloy film 30) and the second layer (WO ₃ film 2)
0), the decomposition temperature (decomposition, sublimation, melting temperature) is 3
When a third layer made of a third substance (for example, hydrocarbon or the like) at a temperature of 00 ° C. or lower is interposed, the performance of retaining recorded information against heat is improved for the following reasons.

That is, by heating to above the decomposition temperature by the recording laser beam, the third substance is decomposed, sublimated, melted, etc., so that the first substance and the second substance can react,
Information can be recorded. Before the recording, by setting the temperature to be equal to or lower than the decomposition temperature, the first substance and the second substance are interposed between the first substance and the second substance.

Here, the reason why the decomposition temperature of the intervening third substance is set to 300 ° C. or lower is that when the temperature is higher than 300 ° C., the power of the laser beam to be applied at the time of recording must be very large, and This is because it is not practical. Also,
On one side of a PET film (substrate), an Al—Ti alloy film (first layer), a WO ₃ film (second layer), a transparent protective film,
As a storage member in which an adhesive layer is sequentially formed, data and an image may be stored by a laser beam, and then the storage member may be attached to an arbitrary place.

As an example without a substrate, for example, T
A MoO ₃ film (second layer) is formed on the i-doped Al foil (first layer).
The layer may be a memory member on which a drawn image can be stored by drawing with a laser beam, or PrO ₂ on a Ti-doped Mg foil (first layer).
The storage member having the obliquely deposited film (second layer) formed thereon may be capable of storing a drawn image by drawing a dot image with an ultrasonic wave.

Further, the first substance is not limited to a metal such as an alloy or an intermetallic compound as containing Ti, but may be TiN.
A material containing a nitride such as (titanium nitride) may be used. For example, a memory member having a TiN film (first layer), a WO ₃ film (second layer), a transparent protective film, and an adhesive layer sequentially formed on one surface of a PET film (substrate) by laser light After storing the data and the image, the data and the image may be attached to an arbitrary place.

In each of the above embodiments, the external energy for inducing a reaction is not limited to laser light, ultrasonic waves, or heat, but includes general light, electromagnetic waves, sound waves, radiation, impact force, distortion, and the like. There may be. It is needless to say that the above embodiments may be appropriately combined.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an overall configuration of a storage member according to the present invention.

FIG. 2 is a sectional view taken along line BB of FIG.

FIG. 3 is a graph showing the relationship between the thickness of an Al—Ti alloy film and the recording laser power.

FIG. 4 is a graph showing the relationship between the thickness of an Al—Ti alloy film and the reflectance of an unrecorded portion.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Memory member, 2 ... Hole, 3 ... Flat part, 4 ... Recording part, 10
... substrate, 11, 12 ... surface of the substrate, 20 ... WO ₃ film, 30
... Al-Ti alloy film, 40 ... Protective film.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yasuhiko Takeda 41-Cho, Yokomichi, Nagakute-cho, Aichi-gun, Aichi Prefecture Inside Toyota Central R & D Laboratories Co., Ltd. 41, Yokomichi, Toyota Central Research Laboratory Co., Ltd. (72) Inventor Tomomi Motohiro 41, Ochi-cho, Yoji, Nagakute-cho, Aichi-gun, Aichi Prefecture 1 Toyota Toyota Central Research Laboratory Co., Ltd. (72) Inventor Shoichi Kawai 1-1-1, Showa-cho, Kariya-shi, Aichi Prefecture Inside Denso Corporation (72) Inventor Yuya Kuno 1-1-1, Showa-cho, Kariya City, Aichi Prefecture Inside Denso Corporation

Claims (1)

[Claims] 1. A multi-layer comprising a first layer made of a first substance and a second layer made of a second substance, wherein the first substance is decomposed from the second substance by applying external energy. A storage member that records information by changing the optical characteristics of at least one of the two substances by performing an oxidation-reduction reaction that supplies oxygen to the substance, wherein the second substance has a 1 mol amount of oxygen molecules. At least one of an oxide and a substance containing oxygen whose energy required for dissociation is 550 kJ or less is used.
Wherein the first substance is a metal whose energy generated when combined with 1 mol of oxygen molecules is 1000 kJ or more;
Ti or T is used for a substance comprising at least one of an intermetallic compound, a nitride, and a compound containing the same.
A memory member comprising an i-compound.